The rectum is a very delicate part of the human body and, as such, requires that it be protected from abrasion, perforation, infection as well as excessive pressure. Accordingly, any device which is intended for rectal insertion should not have any tendency to perforate the rectal wall even in coming into contact with the wall during insertion, must not have sharp contacting edges, and must open the anal sphincter as evenly as possible with the support of maximum circumference of dilation and at a rate which is initially high and gradually reduces to a low rate as dilution reaches a maximum. In the use of a speculum which is intended for the delivery of liquid into the rectum, it is important that water or liquid flow not be concentrated at any spot on the mucosa of the anal canal and which would tend to constantly traumatize an area in the immediate vicinity of the operating position. Further, the speculum should offer the maximum possible aperture for free flow to minimize back pressure during moments of peristalsis. It is also desirable that the speculum be biased so as to be drawn into the rectum under anal contraction and include an anal ring or stop to regulate penetration depth as well as prevent leakage during use.
Various different types and designs of rectal tubes have been devised in the past. For example, U.S. Pat. No. 1,198,742 to C. W. Meinecke discloses a double-ended tubular retainer system to which a discharge tip and inlet may be added. However, the portion which is intended for insertion into the anal canal is a straight parallel tube with offset apertures or openings through which a saline solution is to be discharged. U.S. Pat. No. 1,853,202 to D. B. Catlin similarly employs a relatively straight tube with a gradual forward taper at the leading end. The device is made of a rigid sterilizable material and includes a three-way valve which is manually controlled to determine direction of flow. In U.S. Pat. No. 1,710,701 to H. Hertzberg, an insert tube has a leading, gradually tapered forward tip which forms a solid end of a generally tubular body, the body also being gradually tapered in a forward direction and having forwardly tapered, diametrically opposed apertures or openings which are large enough to permit the passage of liquid as well as solid waste matter. In addition, a shoulder is formed at the trailing end of the tube to limit the depth of penetration into the anal canal. For irrigating purposes, a flexible hose extends from an elevated water bag into the trailing end of the speculum for delivery of water under pressure into the rectum and a drain line is manually closed off by doubling it upon itself during the injection of water. In order to discharge the water from the colon, a larger opening or drain line is opened so as to permit the removal of water and any fecal matter dislodged from the intestinal tract. Nevertheless, the above and other similar types of rectum insertion devices fail to eliminate the possibility of occluding the aperture of the speculum eye thereby causing undue pulling on the mucosa during the drain interval so as to insure the most complete and total elimination as possible as would normally occur during a bowel movement. Other important considerations have to do with the proper dilation of the anal canal during insertion of the speculum followed by anal contraction to effectively lock the speculum in place, proper orientation with respect to the rectum, and at the same time limiting its depth of penetration.
In applicants' copending patent application corresponding to U.S. Ser. No. 247,734 filed Sep. 22, 1988, for "BOWEL CARE APPARATUS", there is set forth and described a novel and improved system for colonic lavage in which a pump circuit is provided to deliver water from a fill receptacle under pressure through a fill line and speculum into the colon, there being a drain line extending away from the speculum and a valve in the drain line which is movable to a closed position when water pressure in the pump exceeds the water pressure in the speculum and to an open position when the water pressure in the speculum exceeds that in the pump.